Ship

ABSTRACT

The invention concerns a ship comprising at least one electric motor for driving a ship and a cooling device for cooling the at least one electric motor by means at least one coolant. It is further according to the invention that the cooling device has a heat exchanger adapted to cool the at least one coolant by means of sea water.

BACKGROUND

1. Technical Field

The invention concerns a ship comprising at least one electric motor fordriving the ship and a cooling device for cooling the at least one motorby means of a coolant. The invention further concerns a cooling devicefor a ship having at least one electric motor.

2. Description of the Related Art

Hitherto the proportion of ships was implemented predominantly by meansof internal combustion engines. Electric drives were also quite oftenused in relation to smaller ships, for example in the leisure industry.In recent times trials are also being undertaken to drive larger ships,such as for example for cargo ships and container ships, by means ofelectric drives. The climate at sea represents a problem for thosedrives which frequently have a complicated and expensive electronicsystem. In particular cooling such electric drives for cargo ships is aproblem which hitherto has been only inadequately resolved.

BRIEF SUMMARY

One or more embodiment of the present invention is to make acontribution to resolving that problem, giving in particular an electricmotor-driven ship with improved cooling.

In a ship of the kind set forth in the opening part of thisspecification a cooling device has a heat exchanger adapted to cool theat least one coolant by means of sea water.

Accordingly a ship according to one embodiment of the invention has atleast two cooling circuits which are coupled together. In a firstcircuit, coolant circulates between the at least one electric motor andthe heat exchanger. In a second circuit, sea water circulates betweenthe heat exchanger and an outside region of the ship. The two circuitsare separated from each other by the heat exchanger in such a way thatcoolant and sea water do not mix. As a result the at least one electricmotor does not come into contact with sea water. Thus, corrosion of theat least one electric motor is substantially reduced and as a result theservice life is substantially prolonged. The maintenance expenditure andcomplication is also substantially reduced. The construction andmanufacture of such an electric motor is also simplified as it does nothave to be designed for direct cooling operation by means of sea water.A further advantage is also that a ship with a drive designed in thatway is improved in terms of energy consumption and reliability. Seawater represents a natural and almost unlimited cooling resource. Thetemperature of the sea water is in that respect substantially constantin a voyage with the ship so that such a cooling device does not requirepermanent adaptive adjustment. In addition there is no need forcomplicated cooling apparatuses to be installed on board a ship wherebyon the one hand operational reliability and on the other hand the energyconsumption of such a ship are improved. Preferably the heat exchangeris in the form of a counter-flow heat exchanger. Alternatively the heatexchanger is the form of a co-flow heat exchanger. According to oneembodiment of the invention it is also possible to use a plurality ofheat exchangers so that the coolant can be cooled in a multi-stage heatexchange process.

In a first preferred embodiment the coolant is air and/or fresh water.According to the invention the term fresh water here does not denote seawater but for example cooling water, cooling fluid and also water-oilemulsions and the like. Air refers here to space air and not to saltysea air. Those two coolants are particularly preferred as they arereadily available and are already used in many cases for electricmotors. In that respect, heat exchange of sea water to fresh water iseasy to implement by virtue of good thermal conduction. Especiallyadapted heat exchangers are preferably to be used for heat exchange fromsea water to air.

In a further preferred embodiment the coolant is air and a rotor and/ora stator of the electric motor can be cooled by means of said air. Inparticular air is preferred for cooling a rotor of an electric motor.The cooled air can be passed for example through a gap between the rotorand the stator, cooling ribs can be arranged at the stator, or coolingpassages through which the cool air can be passed are taken through thestator. In addition the air can be passed into an internal hollow spacein the rotor and thus cool it.

In a further preferred embodiment the at least one electric motor isarranged in a substantially air-tightly closed engine room of the shipand of the air for cooling the electric motor is room air. Thus the atleast one electric motor is not exposed to salty air whereby corrosionof the motor is substantially avoided. That provides that on the onehand maintenance of such a motor or a ship according to the inventionhaving such a motor and such a cooling device is substantially reducedand the operational reliability of the ship is improved. In accordancewith this preferred embodiment, each motor can be provided with adedicated room, or all motors are arranged jointly in a substantiallyair-tightly closed room. In addition an energy supply for the motors canalso be arranged in that room. The heat exchanger can also be arrangedin an air-tightly closed room or can be in fluid communication with thatroom in some other way.

In accordance with a further preferred embodiment means for conveyingair, such as by one or more fans, are arranged at a cooling air inletand/or a warm air outlet of the electric motor. Thus cool air can beguided in specifically targeted fashion to the electric motor or can becaused to impinge thereagainst. That air can also be guided in coolingpassages, over cooling ribs, in openings or hollow spaces or the like tothe electric motor. In addition warm air can be carried away from theelectric motor in a specifically targeted fashion. That makes itpossible to achieve specifically targeted cooling of the motor. Inaddition a specifically targeted volume flow or a specifically targetedair speed can be placed over the motor so that it can be cooled inimproved targeted fashion. That makes it possible to increase theefficiency of the motor and the service life of a motor is prolonged.The maintenance complication and expenditure is also further reduced.

In a further preferred embodiment means for guiding the air is/arearranged between a cooling air inlet of an electric motor and a coolingair outlet of the heat exchanger and/or between a warm air outlet of theelectric motor and a warm air outlet of the heat exchanger. Such meanscan include for example hoses, passages, tubes, shafts and so forth. Aspecifically targeted air feed and discharge is thus afforded accordingto the invention and effective cooling of the motor is improved.Additionally or alternatively the means for guiding the air can havemeans for conveying air. In an embodiment the means for guiding the airare arranged between a cooling air inlet of the electric motor and acooling air outlet of the heat exchanger. In this embodiment cooling airis passed specifically to the motor by means of the means for guidingthe air, the motor is cooled by means of the air supplied thereto, thewarm air is then discharged into the room which is preferablyair-tightly closed. The heated room air is then cooled again by means ofthe exchange effect. In an alternative the means for guiding the air arearranged between a warm air outlet of the electric motor and a warm airinlet of the heat exchanger. In this embodiment the warm air is carriedaway from the electric motor, and towards the heat exchanger, by meansof which it is cooled. The cooled air is then discharged into the roomwhich is preferably air-tightly closed. In a further embodiment themeans for guiding the air are arranged both between a cooling air outletof the heat exchanger and a cooling air inlet of the electric motor, andalso between a warm air outlet of the electric motor and a warm airinlet of the heat exchanger. Accordingly the cooling air circulates in asubstantially closed system. In this embodiment the room does not haveto be air-tightly closed, but rather it is sufficient for the motors tobe protected from salty air.

In a further preferred embodiment the at least one electric motor hascooling passages at a housing and/or at a stator. The cooling passagescan pass through the housing and/or along a stator winding. Specificallytargeted cooling of a motor is possible by means of such coolingpassages. The cooling passages can be designed using various geometries,for example straight, curved, in a zig-zag shape or also in a differentfashion. Ribs can also be arranged in the passages to achieve still moreeffective cooling.

In a further embodiment cooling air can be passed through the coolingpassages and/or a gap between the stator and a rotor. Thatadvantageously develops effective cooling of the electric motor. Meansfor guiding the air and/or means for conveying the air for example canbe connected to the cooling passages.

In a further preferred embodiment the coolant is fresh water which canbe passed through the cooling passages for cooling the electric motor.That permits still more effective cooling of an electric motor. In thisembodiment the fresh water is cooled by means of the heat exchanger,passed through tubes, hoses or the like to the passages, passed throughthe passages and then passed heated again back to the heat exchanger.

In a further preferred embodiment the cooling device has a second heatexchanger which can be connected to a first heat exchanger and which isadapted to cool air by means of fresh water, wherein the fresh water canbe cooled by means of the first heat exchanger by means of sea water.Thus fresh water and air can be cooled with a heat exchanger. It is forexample possible to cool fresh water by sea water with a large primaryheat exchanger, and to pass that fresh water to various motors or otheritems of equipment in the ship such as for example the diesel-generatingassemblies. The electric motors can accordingly each have a respectivededicated second small heat exchanger, by means of which air is cooledby the cool fresh water. The fresh water can then be additionally usedto cool for example the stator of the motor while the cooled air is usedto be passed through a gap between the rotor and the stator and thuscool the rotor. In a further preferred embodiment the first heatexchanger can be connected to a stator of the electric motor and isadapted to cool it by means of the fresh water.

In a further preferred embodiment the energy supply has a converter andthe converter can be cooled by means of fresh water. In particular it ispreferable for those inverters to be cooled by means of the fresh wateras they are preferably arranged in positional proximity with theelectric motors. It is equally preferable for both the converter coolingor the energy supply cooling and the electric motor cooling to bearranged on the same cooling circuit of fresh water. It is however alsopossible to provide different cooling circuits.

In a further aspect of the invention, in a cooling device of the kindset forth in the opening part of this specification, the object isattained in that a cooling device is of a configuration corresponding toone of the above-mentioned embodiments. Such a cooling device can beused in a large number of ships, marine vessels or yachts to cool forexample electric motors or also other devices to be cooled. Such acooling device contributes to making the ship low-maintenance andoperationally reliable and to reduce energy consumption. All theabove-mentioned advantages are achieved when such a cooling device isused in a ship.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The invention is described hereinafter by means of embodiments by way ofexample with reference to the accompanying drawings in which:

FIG. 1 shows a partly broken-away perspective view of a ship accordingto the invention,

FIG. 2 shows a diagrammatic view of a first embodiment of a coolingdevice,

FIG. 3 shows a diagrammatic view of a second embodiment of a coolingdevice,

FIG. 4 shows a diagrammatic view of a third embodiment of a coolingdevice,

FIG. 5 shows a diagrammatic view of a fourth embodiment of a coolingdevice.

DETAILED DESCRIPTION

The ship 102 shown in FIG. 1 has on a deck 114 four Magnus rotors 110 aspropulsion devices. Besides the Magnus rotors 110, the ship alsooptionally has a bridge 130 as well as a crane 105 and a crane 103 onthe deck 114. As a further propulsion device the ship additionally has apropeller 150 at the stern of the ship 102. The propeller 150 can beconnected by way of a shaft 111 to two electric motors 108, 109. Theelectric motors 108, 109 are fed with electric current by way of twoconverter cabinets 115, 116. Arranged above the electric motors 108, 109and the converter cabinets 115, 116 is a deck 172 which preferablyair-tightly closes the engine room in relation to a cargo hold.Preferably large-volume electric motors, for example synchronousmachines, involving a low rotary speed, are used as the electric motors108, 109 so that a transmission does not necessarily have to be providedin the overall drive train. The motors can also be operated selectively.For light to pass into the interior of the ship 102 it has windows 118at the sides.

FIGS. 2 to 4 show embodiments by way of example of a cooling deviceaccording to the invention for a ship 102 according to the invention, bymeans of which the electric motors 108, 109 can be cooled.

As shown in FIG. 2 the cooling device 1 in the first embodiment has aheat exchanger 2 which can be fed on one side 4 with a flow 16 of seawater. The flow of sea water is only diagrammatically indicated here bythe arrows. In the case of a ship 102 as shown in FIG. 1 the sea waterflow 16 can be passed to and away from the heat exchanger 2 by means oftubes. At a second side 6 the heat exchanger 2 has an air inlet 24 andan air outlet 26. Air can thus be cooled by means of this heat exchanger2.

FIG. 2 also shows an electric motor 8. The electric motor 8 has a stator10 which can have a stator housing. The electric motor 8 also has arotor which rotates about an axis of rotation 14 in operation and can becoupled to a drive unit of a ship such as for example a shaft 111 andpropeller 150 (FIG. 1). The electric motor 8 together with itscomponents is arranged in a room 19 which is substantially air-tightlyclosed by a wall 18. The heat exchanger 2 together with its componentsis arranged outside the room 19. The stator or stator housing 10 of theelectric motor 8 also has an air inlet 20 and an air outlet 22. Arrangedthereat as a means for conveying the air is a respective fan 20 a, 22 afor conveying the air into and out of the motor 8; alternatively otherpumps such as vane pumps or the like could be used for that purpose.Preferably the air can be passed through cooling passages in the statoror the stator housing 10 and/or a gap between the rotor 12 and thestator 10. A tube 30 is arranged between the air outlet 22 and the airinlet 24 of the heat exchanger 2. Warm air is carried out of the motor 8and passed to the heat exchanger 2 by way of the tube 30. The cool airwhich issues from the air outlet 26 of the heat exchanger 2 is passed bymeans of a second tube 32 to an air inlet 28 of the room 19 in the wall18. The air passes out of that air inlet 28 into the room 19 so that itis overall filled with cool air. The cool room air is then sucked in bythe fan 20 a at the air inlet 20 and is passed into the cooling passagesof a gap between the rotor 12 and the stator 10. By the room 19 beingfilled with cool air, the fan 20 a in the inlet 20 can suck in air asneeded to cool the motor 8 to a temperature which is preferred foroptimum performance. The motor 8 is also cooled by way of air which isnot blown or sucked directly into the motor 8, but flows along thesurface thereof. Preferably the room 19 is air-tightly closed by meansof the wall 18 or decks, doors, hatches and the like so that in the caseof a ship 102 (FIG. 1) no salty air or as little salty air as possiblepasses into the room 19. Alternatively it is also in accordance with theinvention for the room 19 not to be air-tightly closed, but for anincreased pressure to obtain within the room 19 so that salty air cannotflow from the exterior into the interior of the room 19. It is alsopossible for a tube to be arranged between the inlet 28 of the room 19and the inlet 20 of the motor and/or for no tube 30 to be arrangedbetween the outlet 22 of the motor 8 and the inlet 24 of the heatexchanger 2.

In the second embodiment of the cooling device 1 shown in FIG. 3 thecooling device 1 has a first heat exchanger 2 and a second heatexchanger 3. The two heat exchangers 2, 3 are coupled to a motor 8 andserve to cool it by means of coolant. The first heat exchanger 2 isarranged in a first cooling circuit which substantially corresponds tothe first embodiment shown in FIG. 2 of the cooling device 1. The secondcircuit in which the second heat exchanger 3 is arranged uses freshwater such as for example cooling water or other cooling fluid ascoolant. The second heat exchanger 3 is coupled like the first heatexchanger 2 to a sea water flow 17, wherein that sea water flow 17 onceagain in the case of a ship 102 as shown in FIG. 1 can be passed forexample by way of tubes from an external region of the ship 102 to theheat exchanger 3. The heat exchanger 3 is connected at a second side 7to two cooling water conduits 34, 36 which each have a respective pump38, 40. The pumps 38, 40 are adapted to deliver a corresponding coolingwater flow. The cooling water conduits 34, 36 lead from outside the roomwhere the heat exchanger 3 is also arranged into the interior 19 of theroom and are there connected to a cooling body 42. For that purpose thecooling body 42 has a cooling water inlet 44 and a cooling water outlet46. As shown in FIG. 3 the cooling body 42 is arranged at an outerportion of the motor housing or the stator 10 of the electric motor 8.That is only a diagrammatic view. It is also possible to provide in ahousing or in the stator 10, cooling passages through which coolingwater can be passed. In this embodiment it is possible for example forthe rotor 12 to be substantially cooled with the air which can be passedthrough the air inlet 20 into the interior of the motor 8, and for thestator 10 of the motor 8 to be cooled substantially with water which canbe cooled by way of the heat exchanger 3 by means of the sea water flow17 and which circulates by means of the cooling water conduits 34, 36between the heat exchanger 3 and the cooling body 42.

FIG. 4 shows a further alternative of a cooling device 1. In addition tothe cooling device 1 shown in FIG. 3 the cooling device 1 of FIG. 4 hasa third cooling circuit. The third cooling circuit is fed like thesecond cooling circuit by means of the heat exchanger 3 which is adaptedto cool cooling water by means of a sea water flow 17. As shown in FIG.4 two further cooling water conduits 35,37 branch from the cooling waterconduits 34, 36 and pass cooling water to and away from a convertercabinet 48. The converter cabinet 48 is connected to the electric motor8 by way of a power supply cable 50. Arranged in the converter cabinet48 is a plurality of converters adapted to provide electric current at avoltage and a frequency which are required by the electric motor 8. Toensure optimum operation of a converter cabinet 48 it is preferable forit to be cooled. In the illustrated embodiment the converter cabinet 48or the converters contained therein is cooled with cooling water cooledby means of the heat exchanger 3 by means of a sea water flow 17. Thecooled cooling water is conveyed on a second side 7 of the heatexchanger 3 by a pump 40, and flows through a cooling water feed conduit37 to the converter cabinet 48. A plurality of cooling bodies can bearranged therein, or plates or the like which transport heat away fromthe converters. The heated water is then conveyed away from theconverter cabinet 48 by means of the cooling water conduit 35 and thepump 38 and passes to the heat exchanger 3 again. The two furthercooling circuits are of a configuration corresponding to the circuits inFIG. 3.

A further alternative of the cooling device 1 is shown as an embodimentin FIG. 5. In this embodiment (FIG. 5) the cooling device 1 hassubstantial features in common with the embodiment of FIG. 3. Thecircuits used for cooling the electric motor 8 in the embodiment of FIG.5 are in cascade relationship. The cooling device has a first heatexchanger 2 and a second heat exchanger 3. The heat exchanger 3 has afirst side 5 and a second side 7, wherein a sea water flow 17 can bepassed into the first side 5 and cooling water conduits 34, 36 areconnected to the second side. The first heat exchanger 2 also has afirst side 4 and a second side 6, with two cooling water conduits 52, 54being connected to the first side 4 and two air passages 30, 32 to thesecond side 6. The cooling water conduit 52, 54 lead to the second side7 of the second heat exchanger 3. The co-operation of the air passages30, 32 with the electric motor 8 and the cooling passages 34, 36 withthe cooling element 42 are of a configuration corresponding to theembodiment of FIG. 3. In the present embodiment (FIG. 5) a sea waterflow 17 is used to cool cooling water which then is used on the one handto cool the electric motor 8 by way of a cooling body 42 and on theother hand is used in the first heat exchanger 2 to cool air which thenin turn is used to cool the electric motor 8 and in particular the rotor12. Thus only one sea water access is necessary for the overall coolingsystem and in addition corrosion in the first heat exchanger 2 can bevery substantially avoided.

If more than one motor 8, 108, 109 is arranged in a ship 102 (FIG. 1), acooling device can be provided for each motor or a common cooling devicecan be provided for a plurality of motors. If a cooling device isdesigned for a plurality of motors as in the embodiment of FIG. 5 afirst heat exchanger 2 can be arranged for example for each electricmotor 8, 108, 109, in which case that plurality of first heat exchangers2 co-operative with a single second heat exchanger 3.

The various embodiments described above can be combined to providefurther embodiments. All of the U.S. patents, U.S. patent applicationpublications, U.S. patent application, foreign patents, foreign patentapplication and non-patent publications referred to in thisspecification and/or listed in the Application Data Sheet areincorporated herein by reference, in their entirety. Aspects of theembodiments can be modified, if necessary to employ concepts of thevarious patents, application and publications to provide yet furtherembodiments.

These and other changes can be made to the embodiments in light of theabove-detailed description. In general, in the following claims, theterms used should not be construed to limit the claims to the specificembodiments disclosed in the specification and the claims, but should beconstrued to include all possible embodiments along with the full scopeof equivalents to which such claims are entitled. Accordingly, theclaims are not limited by the disclosure.

1. A ship comprising: a propeller; at least one electric motor fordriving the propeller; and a cooling device that includes a coolant forcooling the at least one electric motor, the cooling device including aheat exchanger adapted to cool the coolant by sea water.
 2. The shipaccording to claim 1 wherein the coolant is at least one of air andfresh water.
 3. The ship according to claim 1 wherein: the coolant isair; and the electric motor includes a rotor and a stator that arecooled by said air.
 4. The ship according to claim 3 wherein the atleast one electric motor is arranged in a substantially air tight engineroom of the ship, and the air for cooling the electric motor is the airin the engine room.
 5. The ship according to claim 3 further comprisingmeans for conveying air through the cooling device, wherein the coolingdevice includes a cooling air inlet and a warm air outlet of theelectric motor.
 6. The ship according to claim 5 further comprisingmeans for guiding the air that is arranged between a cooling air inletof an electric motor and a cooling air outlet of the heat exchanger. 7.The ship according to claim 1 wherein the at least one electric motorincludes a rotor and a stator located in a housing, the cooling deviceincluding cooling passages in at least one of the housing and the statorof the at least one electric motor.
 8. The ship according to claim 7wherein cooling air can be passed through at least one of the coolingpassages and a gap between the stator and the rotor.
 9. The shipaccording to claim 7 wherein the coolant is fresh water that is passedthrough the cooling passages for cooling the electric motor.
 10. Theship according to claim 3 wherein the heat exchanger is a first heatexchanger, the cooling device further including a second heat exchangercoupled to the first heat exchanger, the second heat exchanger beingadapted to cool a coolant by fresh water, wherein the fresh water iscooled by sea water of the first heat exchanger.
 11. The ship accordingto claim 10 wherein the first heat exchanger is coupled to the stator ofthe electric motor and is adapted to cool the stator by means of thefresh water.
 12. The ship according to claim 1 further including anenergy supply that is cooled by the coolant.
 13. The ship according toclaim 12 wherein the energy supply has at least one converter that iscooled by fresh water.
 14. A cooling device for a ship comprising: acooling passage that includes a coolant for cooling at least oneelectric motor; and a heat exchanger located around a portion of thecooling passage and adapted to cool the coolant using sea water.
 15. Thecooling device according to claim 14, the coolant is one of air or freshwater.
 16. The cooling device according to claim 14, wherein the coolingpassage includes an inlet and an outlet, at least one of the inlet andthe outlet including a fan for conveying the coolant through the coolingpassage.
 17. The cooling device according to claim 14, wherein thecooling passage is a first cooling passage that includes air as thecoolant, wherein the heat exchanger is a first heat exchanger, thecooling device further comprising: a second cooling passage thatincludes fresh water coolant for cooling the at least one motor; and asecond heat exchanger located around a portion of the second coolingpassage and adapted to cool the fresh water coolant using sea water. 18.The ship according to claim 5, wherein the means for conveying airthrough the cooling device is a fan arranged at least one of the coolingair inlet and the warm air outlet.
 19. The ship according to claim 5further comprising means for guiding the air is arranged between a warmair outlet of the electric motor and a warm air outlet of the heatexchanger.